1. Technical Field
This application relates to a mobile terminal, a display control method thereof, and a non-transitory computer readable medium storing a display control program.
2. Background Art
A display screen that displays various information is provided on a mobile terminal such as a mobile phone. Visibility of this display screen largely depends on ambient brightness, thus the control for the brightness is an issue to be addressed. Moreover, another issue to be addressed is to save power of the mobile terminal accompanied by the improve in the functions of the mobile terminal. Under those circumstances, control techniques for the display screen of the mobile terminal are under progress in recent years.
As an example of the control techniques for the display screen, there is a technique to adjust brightness of a display screen by a user. Japanese Unexamined Patent Application Publication Nos. 2005-286738, 2006-146030, 2008-219659, 2009-124266, and 2009-300515 disclose techniques in which an illuminance sensor provided on a mobile terminal measures ambient illuminance, and the mobile terminal automatically adjusts brightness of a display screen based on the measured illuminance. Moreover, Japanese Unexamined Patent Application Publication No. 2008-148054 discloses a technique to display only information specified as useful by a user for each event on the mobile terminal and reduce information not necessarily useful for the user.
Further, as the mobile terminals deal with emergency communications, users often leave the mobile terminal by the bed. For example, Japanese Unexamined Patent Application Publication No. 2008-022406 discloses a technique to notify a user of an incoming call or mail received in a limited time zone by light. As described above, many cases occur in which the user activates the mobile terminal and looks at the screen display in the middle of the night in order to respond to an emergency call or incoming mail. With a timer function provided on the mobile terminal such as the mobile phone, the users often use the mobile terminal as an alarm using this timer function. In such a case, the user frequently activates the mobile terminal and looks at the screen display immediately after waking up to check the time.
When the user uses the mobile terminal immediately after waking up from the sleep as in the above case, the brightness of the screen display of the mobile terminal is often adjusted to the level not causing a difficulty for the user to use the mobile terminal in a normal state. If the user looks at the display screen adjusted to the brightness used in the normal state, the user would be suffered from discomfort caused by glare. The screen display with high brightness every time the mobile terminal is activated would also consume unnecessary current.
However, in the system in which the user manually adjusts the brightness of the display screen, the user needs to adjust the brightness every time so as to optimize the display brightness and save the electricity of the terminal, which is inconvenient. Additionally, once the user sets the display screen to high brightness, the user frequently leave the setting of high brightness as it is. In such a case, optimization of the display brightness and power saving of the terminal cannot be achieved.
As in Japanese Unexamined Patent Application Publication Nos. 2005-286738, 2006-146030, 2008-219659, 2009-124266, and 2009-300515, in the abovementioned techniques that adjust the brightness of the display screen by the illuminance sensor, the present inventor has found a problem that the detection operation by the illuminance sensor consumes excessive electricity. The technique disclosed in Japanese Unexamined Patent Application Publication No. 2008-022406 is related to the control for illuminating the display screen in response to an incoming call or mail and not related to reduce the brightness of the screen display.
As a number of symbols called icons are displayed on the display screen of the mobile terminal, the user cannot obtain time information in a glance, for example, that is required by the user, and is forced to search in the display of the mobile terminal for a long time, which poses a problem in usage. Japanese Unexamined Patent Application Publication No. 2008-148054 discloses the technique to reduce the information other than the specified information from the screen and not the technique to set the brightness of the entire display screen.